1. Field of the Invention
This invention relates generally to automotive tooling, and has particular applicability to removal of rivets securing a brake lining to a brake shoe.
2. Description of the Related Art
A common type of brake used in automotive and industrial applications includes a cylindrical brake drum having internal mating brake shoes hydraulically actuated to engage the internal surface of the brake drum. Typically, two segmented brake shoes having curved brake shoe plates matching the drum surface are actuated radially in opposing directions. The brake shoe plate is welded to inward support ribs which can be connected to a wheel or mechanism.
The brake shoes each have a brake lining attached to the surface of the curved plate. Friction between the lining and the rotating drum provides a braking force to slow the rotation of the drum and connected mechanism or wheel. Through repeated use, friction and heat generated during use wear down and deteriorate the brake lining to the point where brake performance is unacceptable. In repairing the brakes of passenger vehicles, the entire brake shoe and the attached brake lining are generally replaced.
However, in the case of trucks and industrial applications, the worn brake lining is removed from the plate of the brake shoe and replaced with a new lining. Replaceable brake linings are attached to the brake shoe plate with rivets which must be removed and replaced during the relining operation. Generally between twenty and thirty-two rivets are arranged in a pattern of rows and columns projecting through the brake lining and brake shoe plate. Different manufactures of brake shoes and different sizes of brake shoes result in multiple patterns of rivet arrangement.
Conventionally, an operator manually removes each rivet individually using a press assembly having a throat into which the brake plate and lining are inserted. The brake shoe is secured in a fixed position by means of a brake shoe support assembly, and the operator moves the press assembly along the plate and lining to remove individual rivets. The press assembly has a hydraulically powered punch rod which extends to engage the rivet and force the rivet through the plate and lining, thereby disengaging the lining. Alternately, a plurality of rivets in a single row are manually expelled using a rivet punch having a plurality of punch rods. This procedure must be repeated for each rivet or row of rivets. Devices which can be used for removing the rivets are described, for example, in U.S. Pat. No. 4,065,843, titled BRAKE SHOE RIVET REMOVAL PRESS, issued Jan. 3, 1978 and U.S. Pat. No. 5,032,129, titled BRAKE SHOE DELINING APPARATUS, issued Aug. 27, 1991.
While the above procedures accomplishes the task of removing the rivets, they are obviously tedious, time-consuming, dangerous to the operator who must manually move the brake shoe along the arcuate path of the press assembly, and subject to failure because of the possible misalignment of the components during any one of the several repositioning steps involved. These procedures also require the undivided attention of the operator for the entire period required to remove the rivets. These factors limit the quantity of shoes that an operator may derivet within a work period and add substantially to the cost of replacing brake linings.